Conductive ink.



UNITED STATES PATENT OFFICE.

HYMAN ELI GOLDBERB, CHICAGO, ILLINOIS.

coNniIcTIvn INK.

No Drawing.

I To all whom it may concern ployed as an ink, and that when spread I have discovered that metals in the colloidal form in a volatile liquid may be emupon a surface and the volatile element evaporated, there is left a metallic layer glycerin. I find that this fluid is perma nent in the sense that no precipitate or sediment is formed at the bottom after hours of standing. When it has dried upon the sheet of paper the metal becomes non-colloidal; that is, insoluble in accordance with the properties of colloidal metals. Moreover, the line or layer is coherent and continuous and electrically conductive. For example, a line of the fluid drawn. by an ordinary pen will conduct electric current.

By a metallic colloid I mean pure metal (not salt of metal) in such finely divided form asnot to precipitate out under the action of gravity from the liquid in which it is diffused. Such metallic colloids can be prepared in a variety of ways. For example, many metals, among them silver, may be rendered colloidal by forming a direct current are under water between terminals consisting of the .metal to be rendered colloidal.

Other conducting material in colloidal form may be substituted for thesilver, for instance, gold, platinum, copper, graphite.

Other l quids may be substituted for the Specification oi. Letters Patent. Application filed August 4, 1911. Serial No. 642,246.

Patented July 30, 1912.

water, for example, alcohol, ether, glycerin, acetone and similar hydrocarbons. I find generall that the marks left upon the paper by a metallic colloid are colored and not black, thus silver colloid will produce gold colored marks or even grass green ones. or rayish black marks. I (Ienerally speaking I find that the most conductive metallic colloids are superior in loid but ordinarily black marks are preferable to colored ones. I, therefore, sometimes employ the pure metal, particularly silver, or again use graphite, or sometimes combine the two with each other and ther by obtain a fluid which has good conductivity, and appears substantially black.

As the colloidal graphite I have used Acheson deflocculated graphite, which I find is colloidal in its nature. This is described and claimed inmy copending application filed October 28th, 1910-, Serial Number Having thus described my invention, what I claim as new, and desire to secure by Let- Colloidal graphite produces black their electrical conductivity to graphite col- A tile liquid wherein the metal and graphite are diffused.

In witness whereof, I have hereunto subscribed my name in the presence of two witnesses.

HYMAN ELI GOLDBERG.

' Witnesses:

MARGARET D. Roma, Max S. Rosnnzwnro. 

